HTTP module can not call callback while same callback is running. #41182

Version

v16.13.1

Platform

Linux playground 5.11.0-41-generic #45~20.04.1-Ubuntu SMP Wed Nov 10 10:20:10 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

HTTP

What steps will reproduce the bug?

var http = require("http")

http
  .createServer(function (req, res) {
    console.log("Req time: ", new Date())
    setTimeout(() => {
      res.write("Hello World!")
      res.end()
    }, 15000)
  })
  .listen(3000)

run this code. it will send response after 15 sec.
make a request and after 2-10 sec make 2nd request to the same url.
It will run the request call back after the 1st request is complete.

How often does it reproduce? Is there a required condition?

It can be reproduce any time.

What is the expected behavior?

It should accept the 2nd request and run the callback immediately.

What do you see instead?

2nd request callback is not firing while first request is not completed.

Additional information

If i send 3rd/4th or more request at the time when first request is pending. After the first request completion all request works as expected. But when all request are completed and we start these steps again, we see the same buggy output.